very true.

as an example...

the 300Z had twins VG30DETT

the 300ZX Z31 had the VG30DET, single turbine on a V6 with one bank's piping being routed over the tranny behind the motor and Y piped into the other so both could feed the turbine.

 

are those still technically called twin-turbos or should they be bi-turbos?

 

Well, as far as the term is used in this country [or rather, how I use the term], any configuration that has two identically sized turbos would be a twin turbo design, whereas if you have one turbo feeding another it's more of a sequential turbo design [or if you have one turbo upstream of another] and two differently sized turbos would closer to a bi-turbo setup [regardless of plumbing scheme] since neither would really be providing useful boost at the same time as the other.

In reality, anything under 6 cylinders only needs one turbo with current technology [ball bearing shafts, etc], and anything that isn't a V configuration 6 or more still doesn't see an advantage using two turbos in place of one larger turbo with a ball bearing supported turbine shaft.

 

Well, a 2-rotor wankel can benefit from sequential turbos to help with lag compared to a big single turbo. But that's different.

 

Hey,

I don't know too much about the specifics of turbos, but I always thought that on a V6 a twin turbo system with a design to reduce turbo lag (One large high flow/high compression turbo which kicks in after the rpm get higher and then one smaller one with less flow and less compression but reacts faster and gives you boost much sooner then the larger turbo takes over)

????? I'm I wrong?

Chris

 

That's a sequential turbo setup, which is also done, but not always the case. Which size turbos are used are up to the owner [whether it is a sequential or twin turbo setup], but generally two are used just for simplicity of plumbing.